A regular problem we have is that it can be hard to find a competent tradesperson to do work that is more complex than a handyman job but too small for most builders to be interested in (eg. general refurbishments to carports or installing a 60m exposed aggregate footpath, or rebuilding retaining walls that were bowing and in danger of collapse due to a lack of proper subsoil drainage). This means it can take a while to get quotes organised. Most quotes have a standard 1 month period for which it is valid printed on the form but then we usually are assured that the quote will be good for longer than that. We have not had problems except where various thing dragged a job out for a year and some of the required work changed.